Avoid double bookings on several platforms: iCal sync delays and what to do

How calendar sync by iCal works

Portals such as Airbnb, Booking.com, Vrbo and FeWo-direkt provide a calendar link for each property that ends in .ics. Terra Mia Immobiliare reads these calendars and shows every booking for your property in one calendar. This works with any portal and any calendar that offers an iCal link, Google Calendar included; you then choose “Other” as the platform. In the other direction, a single export link is enough: it sends bookings made through Terra Mia Immobiliare and the dates you block to every platform where you add it.

The connection therefore has two directions, and you set up each one once. After that, the calendars update automatically. In the owner area you find both in the Calendar step under “Calendar sync”: “Add calendar” for the portals, “Share your availability calendar” for the export link. The individual steps are in Export your Airbnb calendar and sync it with Terra Mia Immobiliare via iCal and Export your Booking.com calendar: iCal sync with Terra Mia Immobiliare, the latter also covering Vrbo, FeWo-direkt and Google Calendar. This article covers the limits of the method and how to deal with them.

Why iCal cannot rule out a double booking

Two clocks run during the sync, and they are not coordinated. Terra Mia Immobiliare reads connected calendars every three hours. When a booking arrives on Airbnb, it can take up to three hours until the next read. In the other direction, each portal decides for itself when it fetches the export link, and with the large portals several hours often pass in between. In that window, a guest on another portal can book days that are already taken. Google also refreshes subscribed calendars on its own schedule.

For a house in Sicily, this matters most in the weeks with the highest prices. In the Terra Mia Immobiliare price index (snapshot of October 29, 2026), August is the most expensive month with a median of 230 EUR per night, July is 189 EUR and January 93 EUR. A week booked twice therefore usually falls in the period when a replacement is hardest to find.

Which dates the export link passes on

The export link contains bookings made through Terra Mia Immobiliare and the dates you block in the calendar yourself. Dates that Terra Mia Immobiliare reads from Airbnb, Booking.com or any other portal are not passed on. That is why you can add the same link to every portal without any portal receiving its own bookings back.

This has a consequence that is often overlooked: a booking that arrives on Airbnb appears in the Terra Mia Immobiliare calendar but does not reach Booking.com through this link, and the same applies the other way round. If you list the house on both portals, also connect Airbnb and Booking.com directly to each other: add each portal's calendar link to the other as an additional calendar, in both directions. Even then, each portal fetches the link on its own schedule. The connection shortens the path of a booking, but a delay remains.

For your blocked dates to reach Terra Mia Immobiliare from a portal, the portal's export options matter. On Booking.com, select booked and closed dates; on Vrbo and FeWo-direkt, leave out tentative reservations.

What iCal transfers

The Terra Mia Immobiliare export link contains only periods: from when to when a property is booked. It contains no prices, names or guest contact details. From the portals' calendars, Terra Mia Immobiliare takes the booked periods and the title the portal gives each entry. iCal does not carry prices, so you keep managing seasonal prices, minimum stays and conditions on each platform yourself. Guest data does not travel through iCal either. Landlords report their guests themselves through the police portal Alloggiati Web ¹, whichever platform the booking comes from.

What happens when bookings overlap

If an entry from a portal overlaps a booking made through Terra Mia Immobiliare, the system detects the overlap. Terra Mia Immobiliare is notified, and it appears as an open task in your owner area. Settle it promptly, before the guest plans further.

Under the mediation terms, bookings from other sources must be blocked in the calendar within 24 hours. A connected calendar helps with that: as long as the connection works, Terra Mia Immobiliare picks up that portal's dates every three hours. You block bookings from sources without a connection in the calendar yourself, such as a direct booking from returning guests or days when you use the house.

If a double booking happens anyway

For bookings through Terra Mia Immobiliare, the mediation terms say: in the event of double bookings, the booking made through Terra Mia Immobiliare takes precedence. If a host cannot honor a booking because of a double booking, the host offers the guest an equivalent alternative or refunds all amounts already paid. If the host is responsible for the double booking, the host owes Terra Mia Immobiliare the commission that would have arisen had the booking gone ahead. For the booking on the other portal, that portal's rules on host cancellations apply. Read them before you reply to the guest.

The guest is therefore not worse off because two portals overlapped: the guest gets an equivalent alternative or the money back. For bookings through Terra Mia Immobiliare, the guest pays the host directly, so the host also makes the refund. The rental contract is formed once the deposit reaches the host within seven days of the booking confirmation.

1. Check which booking came through Terra Mia Immobiliare and which came from another portal.
2. Inform Terra Mia Immobiliare and the affected guest without delay.
3. Offer the guest an equivalent alternative or refund the amounts paid.
4. Block the days on all portals and find out why the sync did not prevent the overlap.

A routine against double bookings

1. Keep one calendar as the overview. The calendar in the owner area shows the bookings of all connected portals. You enter your own blocked dates there, and the export link passes them on.
2. Connect every portal in both directions. Each portal reads the export link, and Terra Mia Immobiliare reads each portal. Connect Airbnb and Booking.com directly as well.
3. Pass on new bookings at once. Block the days right away on the portals that receive them neither directly nor through Terra Mia Immobiliare. Waiting for the next fetch leaves the window open.
4. Block direct bookings and your own use promptly. A 24-hour limit applies to sources without a connection.
5. Check open tasks. Settle an overlap shown in the owner area with Terra Mia Immobiliare.
6. Check the connections. The sync works only as long as the connection does. From time to time, check that new portal bookings appear in the Terra Mia Immobiliare calendar. If you wish, Terra Mia Immobiliare sets up the connection for you.

Next step

Hosts register themselves, and listing is free. A commission of 16% of the total price the guest pays you, plus VAT, is due only when a booking is made. You set up the calendar connection in the Calendar step. How to write a vacation rental listing in Sicily: photos, description, prices, CIN and CIR explains how the listing as a whole comes together.